[PATCH net-next v4 7/9] net: dsa: realtek: rtl8365mb: add family D SDS13 PCS support

[Mieczyslaw Nalewaj <namiltd@yahoo.com>]

Extend the existing RTL8367S SGMII/HSGMII PCS implementation in this
driver for family D switches, whose CPU SerDes is reached through the
indexed SDS13 window and whose SDS_MISC fields differ from family C.

The register sequence and tuning tables are derived from the GPL-licensed
Realtek RTL8367D port API distributed in the Mercusys MR80X GPL release.
Keep the existing family C path unchanged and select the new behavior from
the driver's chip-family metadata, making the implementation reusable by
other family D boards.

This patch only prepares the family D paths; they become reachable
when the RTL8367S-VB chip entry is added in the last patch.

Co-developed-by: Fabiano Tassotti <fabianotassotti@gmail.com>
Signed-off-by: Fabiano Tassotti <fabianotassotti@gmail.com>
Signed-off-by: Mieczyslaw Nalewaj <namiltd@yahoo.com>
---
 drivers/net/dsa/realtek/rtl8365mb_main.c | 226 +++++++++++++++++------
 1 file changed, 173 insertions(+), 53 deletions(-)

diff --git a/drivers/net/dsa/realtek/rtl8365mb_main.c b/drivers/net/dsa/realtek/rtl8365mb_main.c
index f31d72a..d23e80f 100644
--- a/drivers/net/dsa/realtek/rtl8365mb_main.c
+++ b/drivers/net/dsa/realtek/rtl8365mb_main.c
@@ -262,7 +262,8 @@
  * interface, indexed by the external port number with port 5 (the first
  * external port) as the base. Other RTL8367 families index this register
  * differently (e.g. the RTL8367R uses (id + 1) % 2), so this mapping only
- * holds for the RTL8367C-style parts this driver supports.
+ * holds for the RTL8367C-style parts and for family D, where it is the same
+ * (one bit per external port, base port 5), as in the vendor RTL8367D API.
  */
 #define RTL8365MB_BYPASS_LINE_RATE_REG		0x03F7
 #define RTL8365MB_BYPASS_LINE_RATE_MASK(_port)	BIT((_port) - 5)
@@ -284,6 +285,7 @@
 #define   RTL8365MB_SDS_INDACS_CMD_BUSY_MASK	BIT(8)
 #define   RTL8365MB_SDS_INDACS_CMD_RUN_MASK	BIT(7)
 #define   RTL8365MB_SDS_INDACS_CMD_WR_MASK	BIT(6)
+#define   RTL8365MB_SDS_INDACS_CMD_INDEX_MASK	GENMASK(5, 0)
 #define RTL8365MB_SDS_INDACS_ADR_REG		0x6601
 #define RTL8365MB_SDS_INDACS_DATA_REG		0x6602
 
@@ -313,8 +315,10 @@
 #define RTL8365MB_SDS_REG_LINK_STATUS		0x003d
 #define   RTL8365MB_SDS_LINK_STATUS_LINK_MASK	BIT(4)
 
-/* The embedded SerDes can only be muxed to external interface 1 (MAC8),
- * which is port 6.
+/* On family C the embedded SerDes can only be muxed to external interface
+ * 1 (MAC8), which is port 6. Family D has it on external interface 0
+ * (MAC6), see RTL8365MB_D_SDS_EXT0_INDEX. RTL8365MB_SDS_EXT_INTERFACE_ID
+ * below is the family C id; the SerDes port is 6 on both families.
  */
 #define RTL8365MB_SDS_EXT_INTERFACE_ID		1
 #define RTL8365MB_SDS_EXT_INTERFACE_PORT	6
@@ -332,7 +336,22 @@
 #define   RTL8365MB_SDS_OPTION_ARM_KEY		0x0249
 #define RTL8365MB_SDS_OPTION_REG		0x13C1
 
+/* Family D uses the SDS13 indirect window for its MAC6 SerDes. */
+#define RTL8365MB_D_SDS_EXT0_INDEX			13
+#define RTL8365MB_D_FIBER_CFG2_REG			0x13E8
+#define   RTL8365MB_D_FIBER_CFG2_RX_DISABLE_MASK	GENMASK(7, 6)
+#define   RTL8365MB_D_FIBER_CFG2_RX_DISABLE_SDS0	BIT(6)
+#define RTL8365MB_D_SDS_MISC_PA33PC_EN			BIT(11)
+#define RTL8365MB_D_SDS_MISC_PA12PC_EN			BIT(10)
+#define RTL8365MB_D_SDS_MISC_MAC6_SEL_SDS0		BIT(9)
 #define RTL8365MB_D_SDS_MISC_MODE_FIELD_MASK		GENMASK(4, 0)
+#define RTL8365MB_D_SDS_MISC_MODE_SGMII			0x02
+#define RTL8365MB_D_SDS_MISC_MODE_HSGMII		0x12
+#define RTL8365MB_D_SDS_MISC_CFG_MASK			\
+	(RTL8365MB_D_SDS_MISC_PA33PC_EN |		\
+	 RTL8365MB_D_SDS_MISC_PA12PC_EN |		\
+	 RTL8365MB_D_SDS_MISC_MAC6_SEL_SDS0 |		\
+	 RTL8365MB_D_SDS_MISC_MODE_FIELD_MASK)
 /* Shared "disable" encoding for both SDS_MISC's and SDS1_MISC0's
  * 5-bit mode fields.
  */
@@ -720,6 +739,21 @@ static const struct rtl8365mb_jam_tbl_entry rtl8365mb_sds_jam_hsgmii[] = {
 	{ 0x0424, 0xD810 }, { 0x0001, 0x0F80 }, { 0x002E, 0x83F2 },
 };
 
+/* Family D tuning tables from the Realtek vendor port API. */
+static const struct rtl8365mb_jam_tbl_entry rtl8365mb_d_sds_jam_sgmii[] = {
+	{ 0x0427, 0x4E0C }, { 0x0428, 0xAA00 }, { 0x0425, 0x5189 },
+	{ 0x0424, 0x8414 }, { 0x0423, 0x1020 }, { 0x0410, 0x0002 },
+	{ 0x0484, 0x011B }, { 0x0421, 0x8E13 }, { 0x0422, 0x1140 },
+	{ 0x0004, 0x074F },
+};
+
+static const struct rtl8365mb_jam_tbl_entry rtl8365mb_d_sds_jam_hsgmii[] = {
+	{ 0x0427, 0x4E0C }, { 0x0428, 0xAA00 }, { 0x0425, 0x5189 },
+	{ 0x0424, 0x8414 }, { 0x0423, 0x1020 }, { 0x0410, 0x0002 },
+	{ 0x0504, 0x051B }, { 0x0421, 0x8E13 }, { 0x0422, 0x1140 },
+	{ 0x0004, 0x074F },
+};
+
 enum rtl8365mb_phy_interface_mode {
 	RTL8365MB_PHY_INTERFACE_MODE_INVAL = 0,
 	RTL8365MB_PHY_INTERFACE_MODE_INTERNAL = BIT(0),
@@ -1323,7 +1357,8 @@ static int rtl8365mb_ext_config_rgmii(struct realtek_priv *priv, int port,
 	return 0;
 }
 
-static int rtl8365mb_sds_write(struct realtek_priv *priv, u16 addr, u16 data)
+static int rtl8365mb_sds_write(struct realtek_priv *priv, u8 index,
+			       u16 addr, u16 data)
 {
 	int ret;
 
@@ -1341,10 +1376,13 @@ static int rtl8365mb_sds_write(struct realtek_priv *priv, u16 addr, u16 data)
 	 */
 	return regmap_write(priv->map, RTL8365MB_SDS_INDACS_CMD_REG,
 			    RTL8365MB_SDS_INDACS_CMD_RUN_MASK |
-			    RTL8365MB_SDS_INDACS_CMD_WR_MASK);
+			    RTL8365MB_SDS_INDACS_CMD_WR_MASK |
+			    FIELD_PREP(RTL8365MB_SDS_INDACS_CMD_INDEX_MASK,
+				       index));
 }
 
-static int rtl8365mb_sds_read(struct realtek_priv *priv, u16 addr, u16 *data)
+static int rtl8365mb_sds_read(struct realtek_priv *priv, u8 index,
+			      u16 addr, u16 *data)
 {
 	u32 val;
 	int ret;
@@ -1354,7 +1392,9 @@ static int rtl8365mb_sds_read(struct realtek_priv *priv, u16 addr, u16 *data)
 		return ret;
 
 	ret = regmap_write(priv->map, RTL8365MB_SDS_INDACS_CMD_REG,
-			   RTL8365MB_SDS_INDACS_CMD_RUN_MASK);
+			   RTL8365MB_SDS_INDACS_CMD_RUN_MASK |
+			   FIELD_PREP(RTL8365MB_SDS_INDACS_CMD_INDEX_MASK,
+				      index));
 	if (ret)
 		return ret;
 
@@ -1394,6 +1434,14 @@ static int rtl8365mb_sds_probe_option(struct realtek_priv *priv)
 	int ret;
 	int i;
 
+	/* Family D has a fixed SDS13 programming model and does not use the
+	 * family C option register to select its tuning table.
+	 */
+	if (rtl8365mb_get_family(priv) == RTL8365MB_FAMILY_D) {
+		mb->sds_supported = true;
+		return 0;
+	}
+
 	/* Nothing to probe if no external interface is wired to the SerDes */
 	for (i = 0; i < RTL8365MB_MAX_NUM_EXTINTS; i++) {
 		extint = &mb->chip_info->extints[i];
@@ -1472,28 +1520,47 @@ static int rtl8365mb_pcs_config(struct phylink_pcs *pcs, unsigned int neg_mode,
 				const unsigned long *advertising,
 				bool permit_pause_to_mac)
 {
-	const struct rtl8365mb_jam_tbl_entry *sds_jam;
 	const int id = RTL8365MB_SDS_EXT_INTERFACE_ID;
+	const struct rtl8365mb_jam_tbl_entry *sds_jam;
 	struct rtl8365mb *mb = pcs_to_rtl8365mb(pcs);
-	struct realtek_priv *priv;
+	struct realtek_priv *priv = mb->priv;
 	size_t sds_jam_size;
-	u32 mode;
+	u32 misc_mask;
+	u32 misc_val;
+	u32 sds_mode;
+	u8 sds_index;
+	bool is_d;
 	u16 val;
 	int ret;
 	int i;
 
-	priv = mb->priv;
+	is_d = rtl8365mb_get_family(priv) == RTL8365MB_FAMILY_D;
 
+	/* Select the appropriate tuning table and SDS mode */
 	if (interface == PHY_INTERFACE_MODE_2500BASEX) {
-		sds_jam = rtl8365mb_sds_jam_hsgmii;
-		sds_jam_size = ARRAY_SIZE(rtl8365mb_sds_jam_hsgmii);
-		mode = RTL8365MB_EXT_PORT_MODE_HSGMII;
+		if (is_d) {
+			sds_jam = rtl8365mb_d_sds_jam_hsgmii;
+			sds_jam_size = ARRAY_SIZE(rtl8365mb_d_sds_jam_hsgmii);
+			sds_mode = RTL8365MB_D_SDS_MISC_MODE_HSGMII;
+		} else {
+			sds_jam = rtl8365mb_sds_jam_hsgmii;
+			sds_jam_size = ARRAY_SIZE(rtl8365mb_sds_jam_hsgmii);
+			sds_mode = RTL8365MB_EXT_PORT_MODE_HSGMII;
+		}
 	} else {
-		sds_jam = rtl8365mb_sds_jam_sgmii;
-		sds_jam_size = ARRAY_SIZE(rtl8365mb_sds_jam_sgmii);
-		mode = RTL8365MB_EXT_PORT_MODE_SGMII;
+		if (is_d) {
+			sds_jam = rtl8365mb_d_sds_jam_sgmii;
+			sds_jam_size = ARRAY_SIZE(rtl8365mb_d_sds_jam_sgmii);
+			sds_mode = RTL8365MB_D_SDS_MISC_MODE_SGMII;
+		} else {
+			sds_jam = rtl8365mb_sds_jam_sgmii;
+			sds_jam_size = ARRAY_SIZE(rtl8365mb_sds_jam_sgmii);
+			sds_mode = RTL8365MB_EXT_PORT_MODE_SGMII;
+		}
 	}
 
+	sds_index = is_d ? RTL8365MB_D_SDS_EXT0_INDEX : 0;
+
 	/* Hold the embedded DW8051 microcontroller in reset and keep it
 	 * disabled. The vendor driver loads firmware into it to manage the
 	 * SerDes link, but the firmware only duplicates work that phylink
@@ -1522,34 +1589,53 @@ static int rtl8365mb_pcs_config(struct phylink_pcs *pcs, unsigned int neg_mode,
 
 	/* Tune the SerDes with vendor-prescribed parameters */
 	for (i = 0; i < sds_jam_size; i++) {
-		ret = rtl8365mb_sds_write(priv, sds_jam[i].reg,
-					  sds_jam[i].val);
+		ret = rtl8365mb_sds_write(priv, sds_index,
+					  sds_jam[i].reg, sds_jam[i].val);
+		if (ret)
+			return ret;
+	}
+
+	/* Family-specific post-tuning configuration */
+	if (is_d) {
+		ret = regmap_update_bits(priv->map, RTL8365MB_D_FIBER_CFG2_REG,
+					 RTL8365MB_D_FIBER_CFG2_RX_DISABLE_MASK,
+					 RTL8365MB_D_FIBER_CFG2_RX_DISABLE_SDS0);
 		if (ret)
 			return ret;
+
+		misc_mask = RTL8365MB_D_SDS_MISC_CFG_MASK;
+		misc_val  = RTL8365MB_D_SDS_MISC_PA33PC_EN |
+			    RTL8365MB_D_SDS_MISC_PA12PC_EN |
+			    RTL8365MB_D_SDS_MISC_MAC6_SEL_SDS0 | sds_mode;
+	} else {
+		/* Mux the SerDes to MAC8 in the requested mode */
+		misc_mask = RTL8365MB_SDS_MISC_MAC8_SEL_SGMII_MASK |
+			    RTL8365MB_SDS_MISC_MAC8_SEL_HSGMII_MASK;
+		misc_val  = (sds_mode == RTL8365MB_EXT_PORT_MODE_SGMII) ?
+			    RTL8365MB_SDS_MISC_MAC8_SEL_SGMII_MASK :
+			    RTL8365MB_SDS_MISC_MAC8_SEL_HSGMII_MASK;
 	}
 
-	/* Mux the SerDes to MAC8 in the requested mode */
 	ret = regmap_update_bits(priv->map, RTL8365MB_SDS_MISC_REG,
-				 RTL8365MB_SDS_MISC_MAC8_SEL_SGMII_MASK |
-					 RTL8365MB_SDS_MISC_MAC8_SEL_HSGMII_MASK,
-				 mode == RTL8365MB_EXT_PORT_MODE_SGMII ?
-					 RTL8365MB_SDS_MISC_MAC8_SEL_SGMII_MASK :
-					 RTL8365MB_SDS_MISC_MAC8_SEL_HSGMII_MASK);
+				 misc_mask, misc_val);
 	if (ret)
 		return ret;
 
-	val = mode << RTL8365MB_DIGITAL_INTERFACE_SELECT_MODE_OFFSET(id);
-	ret = regmap_update_bits(priv->map,
-				 RTL8365MB_DIGITAL_INTERFACE_SELECT_REG(id),
-				 RTL8365MB_DIGITAL_INTERFACE_SELECT_MODE_MASK(id),
-				 val);
-	if (ret)
-		return ret;
+	if (!is_d) {
+		val = sds_mode << RTL8365MB_DIGITAL_INTERFACE_SELECT_MODE_OFFSET(id);
+		ret = regmap_update_bits(priv->map,
+					 RTL8365MB_DIGITAL_INTERFACE_SELECT_REG(id),
+					 RTL8365MB_DIGITAL_INTERFACE_SELECT_MODE_MASK(id),
+					 val);
+		if (ret)
+			return ret;
+	}
 
 	/* Take the SerDes out of reset. The vendor driver does this only
 	 * after the SerDes mux and the interface mode are configured.
 	 */
-	ret = rtl8365mb_sds_write(priv, RTL8365MB_SDS_REG_RESET,
+	ret = rtl8365mb_sds_write(priv, sds_index,
+				  RTL8365MB_SDS_REG_RESET,
 				  RTL8365MB_SDS_RESET_DEASSERT);
 	if (ret)
 		return ret;
@@ -1559,27 +1645,32 @@ static int rtl8365mb_pcs_config(struct phylink_pcs *pcs, unsigned int neg_mode,
 	 * This flushes the FIFOs and ensures a clean state for the link,
 	 * preventing silent drops and CRC errors.
 	 */
-	ret = rtl8365mb_sds_write(priv, RTL8365MB_SDS_REG_BMCR,
+	ret = rtl8365mb_sds_write(priv, sds_index,
+				  RTL8365MB_SDS_REG_BMCR,
 				  RTL8365MB_SDS_BMCR_DPRST_PHASE1);
 	if (ret)
 		return ret;
 
-	ret = rtl8365mb_sds_write(priv, RTL8365MB_SDS_REG_BMCR,
+	ret = rtl8365mb_sds_write(priv, sds_index,
+				  RTL8365MB_SDS_REG_BMCR,
 				  RTL8365MB_SDS_BMCR_DPRST_PHASE2);
 	if (ret)
 		return ret;
 
 	/* Keep SGMII in-band autonegotiation disabled: the link parameters are
-	 * forced from rtl8365mb_pcs_link_up() instead.
+	 * forced from rtl8365mb_pcs_link_up() instead (family C), or from
+	 * mac_link_up() (family D).
 	 */
-	ret = rtl8365mb_sds_read(priv, RTL8365MB_SDS_REG_NWAY, &val);
+	ret = rtl8365mb_sds_read(priv, sds_index,
+				 RTL8365MB_SDS_REG_NWAY, &val);
 	if (ret)
 		return ret;
 
 	val &= ~RTL8365MB_SDS_NWAY_EN_MASK;
 	val |= RTL8365MB_SDS_NWAY_RESTART_MASK;
 
-	return rtl8365mb_sds_write(priv, RTL8365MB_SDS_REG_NWAY, val);
+	return rtl8365mb_sds_write(priv, sds_index,
+				   RTL8365MB_SDS_REG_NWAY, val);
 }
 
 static bool rtl8365mb_interface_is_serdes(phy_interface_t interface)
@@ -1604,18 +1695,27 @@ static void rtl8365mb_pcs_get_state(struct phylink_pcs *pcs,
 {
 	struct rtl8365mb *mb = pcs_to_rtl8365mb(pcs);
 	struct realtek_priv *priv = mb->priv;
+	u8 sds_index = 0;
 	u16 status;
+	bool is_d;
 	u32 val;
 	int ret;
 
-	/* In-band autonegotiation is not implemented, so the link parameters are
-	 * forced from rtl8365mb_pcs_link_up(). The real link state must still be
-	 * read from the SerDes itself: the embedded DW8051 microcontroller that
+	is_d = rtl8365mb_get_family(priv) == RTL8365MB_FAMILY_D;
+
+	/* In-band autonegotiation is not implemented, so the link parameters
+	 * are forced from rtl8365mb_pcs_link_up() on family C, and from
+	 * mac_link_up() on family D. The real link state must still be read
+	 * from the SerDes itself: the embedded DW8051 microcontroller that
 	 * the vendor firmware uses to poll the SerDes is kept disabled (see
 	 * rtl8365mb_pcs_config()), so the link status register can be read
 	 * directly through the SDS_INDACS window without racing the auto-poll.
 	 */
-	ret = rtl8365mb_sds_read(priv, RTL8365MB_SDS_REG_LINK_STATUS, &status);
+	if (is_d)
+		sds_index = RTL8365MB_D_SDS_EXT0_INDEX;
+
+	ret = rtl8365mb_sds_read(priv, sds_index,
+				 RTL8365MB_SDS_REG_LINK_STATUS, &status);
 	if (ret) {
 		state->link = false;
 		return;
@@ -1626,6 +1726,17 @@ static void rtl8365mb_pcs_get_state(struct phylink_pcs *pcs,
 	if (!state->link)
 		return;
 
+	if (is_d) {
+		/* Only 2500base-x is a fixed rate; for the other modes keep
+		 * the speed and duplex phylink passed in.
+		 */
+		if (state->interface == PHY_INTERFACE_MODE_2500BASEX) {
+			state->duplex = DUPLEX_FULL;
+			state->speed = SPEED_2500;
+		}
+		return;
+	}
+
 	/* The speed and duplex are forced; read them back from the values
 	 * programmed into the SerDes MISC register.
 	 */
@@ -1667,6 +1778,12 @@ static void rtl8365mb_pcs_link_up(struct phylink_pcs *pcs,
 	u32 r_speed;
 	int ret;
 
+	/* Family D forces the external MAC ability from mac_link_up(); its
+	 * SDS_MISC fields do not share the family C link-force layout.
+	 */
+	if (rtl8365mb_get_family(priv) == RTL8365MB_FAMILY_D)
+		return;
+
 	/* The speed field has no value for 2.5 Gbps: the rate is determined by
 	 * the HSGMII SerDes configuration, and the vendor driver programs the
 	 * 1 Gbps value here.
@@ -1985,18 +2102,21 @@ static void rtl8365mb_phylink_mac_link_up(struct phylink_config *config,
 			return;
 		}
 
-		/* The SerDes has its own pause enables; program them from
-		 * the resolved pause modes, as the vendor driver does when
-		 * forcing the link on a SerDes external interface. These
-		 * bits, not the MAC force pause bits, gate pause on the
-		 * SerDes external interface: flow control testing shows
-		 * that pause frames are only emitted with the SerDes TXFC
-		 * bit set, while the MAC force pause bits alone have no
-		 * effect on this port. This is done here rather than in
-		 * rtl8365mb_pcs_link_up() because pcs_link_up() carries no
-		 * pause information.
+		/* Family C: the SerDes has its own pause enables; program
+		 * them from the resolved pause modes, as the vendor driver
+		 * does when forcing the link on a SerDes external
+		 * interface. These bits, not the MAC force pause bits, gate
+		 * pause on the SerDes external interface: flow control
+		 * testing shows that pause frames are only emitted with the
+		 * SerDes TXFC bit set, while the MAC force pause bits alone
+		 * have no effect on this port. This is done here rather
+		 * than in rtl8365mb_pcs_link_up() because pcs_link_up()
+		 * carries no pause information. Family D does not use this
+		 * path: its pause bits are set in the forced-mode register
+		 * by rtl8365mb_ext_config_forcemode().
 		 */
-		if (rtl8365mb_interface_is_serdes(interface)) {
+		if (rtl8365mb_interface_is_serdes(interface) &&
+		    rtl8365mb_get_family(priv) != RTL8365MB_FAMILY_D) {
 			u32 val = 0;
 
 			if (tx_pause)
-- 
2.53.0